1. Field of the Invention
The present invention relates to a sealing device for mechanical parts, and more particularly to a sealing device, which is comprised of an inner race, an outer race capped on and rotatable relatively to the inner race, and a rubber oil seal mounted in between the inner race and the outer race.
2. Description of the Related Art
In machinery, sealing devices are used in parts of transmission (rotary) mechanisms, such as rotary shafts, for protection against outside dust and prevention of leakage of internal lubricating oil. To achieve a satisfactory sealing effect, elastic rubber is commonly used as the major part of the sealing device. The functioning of the elastic rubber determines the sealing effect of the sealing device. It is known that temperature is one of the major factors that cause the deterioration of the elastic rubber. A high working temperature accelerates aging of the elastic rubber. Friction between the parts, radiation of sunlight, and temperature change of lubricating oil cause the elastic rubber to deteriorate. Therefore, the ambient temperature has a great concern with the service life of the elastic rubber. It is a practical way to prolong the service life of a sealing device by preventing increase of the working temperature.